METHOD FOR PRODUCING A BUILDING BOARD WITH HIGH FIRE RESISTANCE

Description

[0001] The invention relates to a method for producing a building board with high fire resistance.

[0002] Construction boards are used in drywall construction. For example, construction boards are used as cladding elements in drywall construction, for example, to cover walls or pipes. Construction boards are also used, for example, to create partition walls. In particular, construction boards are also used to create ventilation ducts.

[0003] DE 24 61 781 A discloses a composition for producing molded articles, which may comprise, among other ingredients, calcium silicate binder, fibers, perlite, and water. DE 34 28 880 A discloses a process for producing fire-resistant calcium silicate molded articles, which comprises, among other ingredients, mixing xonotlite gel with perlite and subsequently compressing and drying the mixture.

[0004] For fire protection reasons, building boards with high fire resistance, which are also known as fire protection boards, are regularly required.

[0005] Building boards with high fire resistance are known, for example, in the form of building boards made of hydraulically set cement, in particular hydraulically set Portland cement and high-alumina or high-alumina cement.

[0006] Furthermore, fire protection boards with high fire resistance are also known in the form of calcium silicate boards, i.e. in the form of building boards based on at least one mineralogical phase in the ternary system CaO-SiO 2 -H 2 O. A mineralogical phase from this ternary system is regularly referred to as a CSH phase, and a building board produced on the basis of such a phase is referred to as a CSH building board.

[0007] In the ternary system CaO-SiO 2 -H 2 O, there are numerous mineralogical phases that differ from one another in terms of their respective proportions of the phases CaO, SiO 2, and H 2 O. A common mineralogical phase in the ternary system CaO-SiO 2 -H 2 O, on the basis of which building panels are manufactured, is, for example, the mineralogical phase tobermorite with the chemical formula Ca 5 Si 6 O 17 5 H 2 O.

[0008] However, many of the substances from which building boards are regularly made do not give the building board a high level of fire resistance because these substances decompose or burn when exposed to high, long-term temperature stress, for example.

[0009] However, to offer high fire resistance, building panels must be able to withstand continuous exposure to high temperatures for a longer period of time.

[0010] Furthermore, it is often desirable for the building boards to have the lowest possible density. Despite the low density, it is also often desirable for the boards to have high mechanical stability, especially under mechanical stress. At the same time, it is desirable for the building boards to be easy to process mechanically, for example, by drilling, stapling, or sawing.

[0011] The object of the present invention is to provide a method for producing a building board with high fire resistance.

[0012] A further object of the invention is to provide such a method for producing a building board with high fire resistance, which at the same time can be provided with a low density.

[0013] A further object of the invention is to provide such a method for producing a building board with high fire resistance, which can be provided with a low density and yet at the same time with a high mechanical stability, even when exposed to high temperatures for a long period of time.

[0014] A further object of the invention is to provide such a method for producing a building board with high fire resistance, which can be provided with a low density and yet at the same time with a high mechanical stability, even when exposed to high temperatures for a longer period of time, wherein the building board is at the same time mechanically easy to process.

[0015] In order to be able to provide such a method, the invention provides a method according to claim 1.

[0016] The invention is based on the surprising finding that the above objects can be achieved by a method according to claim 1.

[0017] Xonotlite is a calcium silicate with hydroxide ions, or a calcium silicate hydrate, from the ternary system CaO-SiO 2 -H 2 O. Xonotlite has the chemical formula Ca 6 [Si 6 O 17 ](OH) 2.

[0018] The advantage of the xonotlite component in the building board is that it is non-flammable and only begins to decompose at temperatures of around 900°C. This gives the building board high fire resistance. At the same time, xonotlite's high strength provides the building board with high mechanical stability. Another advantage of xonotlite is that this phase is harmless to health, making the building board suitable for indoor use.

[0019] Preferably, the building board comprises xonotlite in a proportion of at least 20 mass%, more preferably in a proportion in the range of 20 to 50 mass% and even more preferably in a proportion in the range of 20 to 40 mass%.

[0020] The information given herein with regard to the mass fraction of a component of the building board in mass% always refers to the total mass of the building board, unless otherwise stated in the individual case.

[0021] The use of expanded perlite in building boards offers significant advantages. Expanded perlite has a low density, meaning it contains only a small amount of expanded perlite, which allows the board to be manufactured with a low density. At the same time, expanded perlite is mechanically stable and highly fire-resistant, meaning that the use of expanded perlite in building boards can also produce a building board with high mechanical stability, particularly when exposed to high temperatures for extended periods. Furthermore, expanded perlite is harmless to health, making it ideal for indoor use. Furthermore, the building board is easy to machine due to the expanded perlite content.

[0022] In particular, it has surprisingly also been found according to the invention that expanded perlite is particularly advantageous for the building board for reasons arising from the production of a building board. For example, the open pore volume of the expanded perlite can be partially filled with xonotlite. This is due to the fact that the components forming the xonotlite (i.e. in particular a component comprising calcium oxide, a component comprising silicon dioxide and water) penetrate into the open pore volume of the expanded perlite during the production of the building board, form xonotlite there and accordingly at least partially fill the open pores of the expanded perlite with xonotlite. This at least partial filling of the open pores of the expanded perlite with xonotlite proves to be advantageous for several reasons.The absorbency of the expanded perlite is significantly reduced by filling the open pores with xonotlite, so that only a small amount of paint or water-repellent agent is required for any impregnation of the building board, for example with a paint coating or hydrophobic treatment, since the expanded perlite largely only absorbs this substance superficially. However, this can be particularly advantageous if such an impregnation contains organic components that could impair the fire resistance of the building board. Furthermore, it has surprisingly been found that the mechanical stability of the expanded perlite is increased by the xonotlite partially embedded in the open porosity of the expanded perlite. This also increases the overall mechanical stability of the building board.

[0023] In this respect, according to a particularly preferred embodiment, the open pores of the expanded perlite are partially filled with xonotlite.

[0024] Surprisingly, it has been found according to the invention that the grain size of the expanded perlite in the building board can be particularly important for the mechanical stability of the building board, especially under fire exposure. Thus, the mechanical stability of the building board can be increasingly increased if the expanded perlite is increasingly present in the building board with a grain size of no more than 1.5 mm. In this respect, a particularly preferred embodiment provides that the expanded perlite is largely or even entirely present with a grain size of no more than 1.5 mm.

[0025] According to a preferred embodiment, at least 50 mass%, more preferably at least 90 mass%, and even more preferably 100 mass% of the expanded perlite has a grain size below 1.5 mm. Furthermore, at least 50 mass%, more preferably at least 90 mass%, and even more preferably 100 mass% of the expanded perlite has a grain size in the range of 0.01 to 1.5 mm. The stated mass fractions of expanded perlite in a specific grain size are each based on the total mass of expanded perlite in the building board.

[0026] The grain size of the expanded perlite in the building board can preferably be determined on the basis of a polished section of the building board, in particular by a microscopic analysis of the polished section, particularly preferably microscopically by imaging, computer-aided analysis programs.

[0027] Preferably, the building board comprises the expanded perlite in a proportion in the range of 8 to 20 mass%, more preferably in a proportion in the range of 10 to 15 mass%.

[0028] The fibers in the building board can further increase its mechanical strength. The building board thus forms a fiber-reinforced composite material, with the fibers embedded in the matrix of the building board formed from the xonotlite.

[0029] Preferably, the building board comprises fibers in a proportion in the range of 1.5 to 10 mass%, more preferably in a proportion in the range of 2 to 8 mass%.

[0030] According to a particularly preferred embodiment, the fibers are in the form of at least one of the following types of fibers: organic fibers or inorganic fibers.

[0031] Organic fibers may preferably be in the form of at least one of the following types of fibers: cellulose fibers or carbon fibers. If the organic fibers are in the form of cellulose fibers, they may particularly preferably be in the form of kraft cellulose fibers.

[0032] Cellulose fibers, in particular in the form of kraft cellulose fibers, are preferably contained in the building board in a proportion in the range of 1 to 6% by mass, more preferably in a proportion in the range of 1 to 4% by mass.

[0033] Preferably, the cellulose fibers, in particular in the form of kraft cellulose fibers, have at least one of the following geometries: an average fiber diameter in the range of 10 to 30 µm or an average fiber length in the range of 0.5 to 3 mm.

[0034] Inorganic fibers may preferably be in the form of glass fibers, particularly preferably in the form of at least one of the following types of glass fibers: AES fibers, mineral fibers, basalt fibers, alumina fibers (Al 2 O 3 fibers) or silicate fibers (SiO 2 fibers).

[0035] According to a particularly preferred embodiment, the glass fibers are in the form of AES fibers. "AES fibers" (= alkaline earth silicate fibers) are known to be glass fibers based on the material system MgO-CaO-SiO 2 , i.e., alkaline earth silicate fibers. Particularly preferably, the AES fibers are highly pure, i.e., with only a very small proportion of other oxides besides the oxides MgO, CaO, and SiO 2 , as this gives the fibers high fire resistance and the ability to withstand high application temperatures. A particular advantage of AES fibers is that they are not classified as hazardous substances and, in particular, are not carcinogenic, so that the building board, as long as it contains AES fibers, can be used indoors without any problems.If the glass fibers are in the form of AES fibers, they preferably have a chemical composition with a SiO 2 content of at least 60 mass%, more preferably with a content in the range of 60 to 90 mass%, even more preferably with a content in the range of 60 to 85 mass%, and even more preferably with a content in the range of 70 to 85 mass%. Furthermore, if the AES fibers have the above chemical contents of SiO 2, they preferably have a chemical composition with a content of MgO and CaO in a total mass in the range of 10 to 40 mass%, even more preferably with a content in the range of 15 to 40 mass%, and even more preferably with a content in the range of 15 to 30 mass%. According to a preferred embodiment, it is provided that the AES fibers, insofar as they have the above chemical proportions of SiO 2 , MgO and CaO, have a proportion of further chemical substances in a proportion of less than 3% by mass.The above information on the chemical composition of the AES fibers is based on the total mass of the glass fibers in the building board.

[0036] The building board preferably comprises glass fibers, in particular in the form of AES fibers, in a proportion in the range of 0.5 to 5 mass%, more preferably in a proportion in the range of 0.5 to 4 mass%.

[0037] The building board preferably comprises glass fibers, in particular with the above chemical composition, which have a classification temperature according to DIN EN 1094-1:2008-09 of at least 1,200°C.

[0038] The glass fibers preferably have an average fiber diameter in the range of 5 to 10 µm, more preferably in the range of 7 to 9 µm.

[0039] Preferably, the AES fibers have at least one of the following geometries: an average fiber diameter in the range of 5 to 15 µm (more preferably in the range of 7 to 9 µm) or an average fiber length in the range of 1 to 10 mm.

[0040] According to a particularly preferred embodiment, the fibers are in the form of AES fibers and kraft cellulose fibers.

[0041] In the building board, xonotlite forms a matrix in which the expanded perlite and the fibers are embedded.

[0042] The expanded perlite and fibers are preferably evenly distributed throughout the volume of the building board.

[0043] As explained above, building boards with high fire resistance, in particular so-called fire protection boards, are known, particularly in the form of cement-bonded boards, in particular based on hydraulically setting cements such as Portland cements and high-alumina cements, in particular high-alumina cements. However, according to the invention, it was found that such cements can impair the fire resistance and, in particular, the mechanical strength of the building board. In particular, these cements can also adversely affect the mechanical stability of the xonotlite when the building board is exposed to temperature. Therefore, according to a preferred embodiment, the building board contains no or only minimal amounts of cement, in particular Portland cements, high-alumina cements, or high-alumina cements.

[0044] Preferably, the building board contains cements, in particular hydraulically setting cements, in particular Portland cements, high-alumina cements and high-alumina cements, only in a proportion of less than 10% by mass, more preferably in a proportion of less than 5% by mass and even more preferably in a proportion of less than 1% by mass.

[0045] According to a preferred embodiment, the building board comprises xonotlite, the expanded perlite, and the fibers in a proportion of at least 33 mass%. Furthermore, it can preferably be provided that the building board comprises the xonotlite, the expanded perlite, and the fibers in a proportion of at most 63 mass%. According to a preferred embodiment, the building board comprises xonotlite, the expanded perlite, and the fibers in a proportion in the range of 33 to 63 mass%, more preferably in a proportion in the range of 35 to 55 mass%.

[0046] The building board may also contain anhydride as a further component.

[0047] Such a component in the form of anhydride, i.e., CaSO4, has the particular advantage that the xonotlite is stabilized by the anhydride, especially when the building board is exposed to high temperatures. Thus, the anhydride decomposes endothermically at temperatures above approximately 1,180°C, which can cool the building board and delay the decomposition of the xonotlite.

[0048] Preferably, the building board comprises anhydride in a proportion in the range of 0.5 to 5 mass%, more preferably in a proportion in the range of 0.8 to 2 mass%.

[0049] The building board may also contain calcium carbonate as an additional component.

[0050] Calcium carbonate, i.e. CaCO 3 , can be present in the building board in at least one of the following mineralogical phases: calcite, aragonite or vaterite.

[0051] Like anhydride, calcium carbonate also has the advantage of stabilizing xonotlite in the building board, especially when exposed to high temperatures. Calcium carbonate begins to decompose endothermically at temperatures of approximately 825°C, which also cools the building board and inhibits the decomposition of the xonotlite.

[0052] Preferably, the building board comprises calcium carbonate in a proportion in the range of 1 to 10 mass%, more preferably in a proportion in the range of 1 to 5 mass%.

[0053] According to a preferred embodiment, the building board comprises the xonotlite, the expanded perlite, the fibers, the anhydride, and the calcium carbonate in a proportion of at least 35% by mass. Furthermore, it can preferably be provided that the building board comprises the xonotlite, the expanded perlite, the fibers, the anhydride, and the calcium carbonate in a proportion of at most 70% by mass. According to a preferred embodiment, the building board comprises the xonotlite, the expanded perlite, the fibers, the anhydride, and the calcium carbonate in a proportion in the range of 35 to 70% by mass, more preferably in a proportion in the range of 37 to 57% by mass.

[0054] During the production of the building board by the process according to the invention, as described in more detail below, the formation of further phases may occur. These further phases may, in particular, be phases in the ternary system CaO-SiO 2 -H 2 O that are not present in the form of xonotlite (hereinafter referred to as "further CSH phases"). In particular, these further CSH phases may be present in the form of at least one of the following phases: scawtite (Ca 7 Si 6 O 18 CO 3 (H 2 O) 2 ), tobermorite, or X-ray amorphous calcium silicate phases (so-called "calcium silicate gel phases" or "CS gel phases").

[0055] In this respect, it can preferably be provided that the building board comprises such further CSH phases in a proportion of less than 65% by mass, in particular in a proportion in the range of 30 to 65% by mass and even more preferably in a proportion in the range of 43 to 63% by mass.

[0056] Preferably, the building board comprises tobermorite in a proportion of at most 25 mass%, more preferably in a proportion in the range of 10 to 25 mass% and even more preferably in a proportion in the range of 10 to 20 mass%.

[0057] Preferably, the building board comprises Scawtite in a proportion of at most 10 mass%, more preferably in a proportion in the range of 1 to 10 mass% and even more preferably in a proportion in the range of 1 to 8 mass%.

[0058] The building board preferably comprises X-ray amorphous calcium silicate phases in a proportion in the range of 20 to 30 mass%.

[0059] According to one embodiment, the building board may comprise the xonotlite, the expanded perlite, the fibers, the anhydride, the calcium carbonate, and the other CSH phases in a total mass of at least 92% by mass. According to one embodiment, the building board may comprise the xonotlite, the expanded perlite, the fibers, the anhydride, the calcium carbonate, and the other CSH phases in a proportion in the range of 92 to 100% by mass, and more preferably in a proportion in the range of 96 to 100% by mass.

[0060] The building board may comprise quartz components, which may result in particular from the production of the building board, in particular by the method according to the invention as described in more detail below. The building board preferably comprises quartz in a proportion of at most 10% by mass, more preferably in a proportion in the range of 1 to 10% by mass, and even more preferably in a proportion in the range of 1 to 5% by mass.

[0061] The mineralogical composition of the plate is preferably determined by X-ray diffraction analysis, particularly preferably by the Rietveld method.

[0062] With regard to the chemical composition of the plate, it preferably has a SiO 2 content of 40 to 50 mass%, more preferably 42 to 48 mass%, and a CaO content of 35 to 45 mass%, more preferably 36 to 43 mass% and even more preferably 38 to 43 mass%.

[0063] The chemical composition of the plate is determined by X-ray fluorescence analysis according to DIN EN ISO 12677: 2013-02.

[0064] Furthermore, the chemical composition of the board may exhibit a loss on ignition in a range of 5 to 15 mass%. The loss on ignition may be caused, in particular, by crystal water and cellulose fibers in the construction board.

[0065] Preferably, the plate has a chemical composition with a proportion of Al 2 O 3 below 3 mass%, in particular in the range from 1 to < 3 mass%.

[0066] Furthermore, the board preferably has a chemical composition according to which Fe 2 O 3 , SO 3 , MgO, K 2 O and Na 2 O are each present in a proportion of less than 1% by mass, wherein one, several or all of these substances can be present in the building board in such a proportion of less than 1% by mass.

[0067] Preferably, the plate has a chemical composition such that the proportion of SiO 2 and CaO is at least 80% by mass and preferably a proportion of SiO 2 and CaO in the range of 80 to 90% by mass, more preferably in a proportion in the range of 82 to 88% by mass.

[0068] Furthermore, with regard to the chemical composition of the building board, the mass ratio of CaO to SiO 2 is preferably below 1.0 and in particular in the range from 0.85 to < 1.0.

[0069] Due to the expanded perlite in the building board, it is possible to provide it with a low density. The building board preferably has a density of no more than 900 kg / m³. The density of the building board is particularly preferably in the range of 400 to 900 kg / m³. The density is determined after drying at 105°C to constant weight.

[0070] The building board preferably has a thickness in the range of 10 to 60 mm.

[0071] Due to its high mechanical stability, especially under fire exposure, the construction board can be supplied in a very long length. The construction board can be up to 2.5 m long.

[0072] In particular, the building board can meet the classification "Non-combustible A1" according to DIN EN 13501-1: 2010-01.

[0073] In particular, the building board can be provided with a high level of fire resistance, while remaining mechanically stable even under continuous fire exposure. In particular, the building board demonstrates mechanical stability for at least 90 minutes when exposed to temperature according to the standard temperature curve according to DIN EN 1363-1:2012-10.

[0074] The building board is preferably cured in an autoclave, as described below. After curing in the autoclave, the building board can be provided with additional components, such as an impregnation (such as a water-repellent coating or other coating), a lamination (such as a metal lamination), or fastening elements (such as clamps, screwed-on profiles, etc.). These additional components are not included in the above-mentioned information on the mass proportions of the building board components in the total mass of the building board.

[0075] For producing a building board with high fire resistance, the invention provides a method comprising the following steps: Providing an offset comprising: a component comprising calcium oxide; a component comprising silica; expanded perlite with a high open porosity; fibers; and water; Forms of offset; Applying pressure and temperature to the formed batch such that the calcium oxide component, the silicon dioxide component and the water form xonotlite.

[0076] The method according to the invention is particularly preferably used to produce a building board described herein, so that the building board produced by the method according to the invention can particularly preferably have the features of the building board described herein.

[0077] The method according to the invention is based in particular on the surprising finding that building boards with high fire resistance and the properties of the building board described in more detail herein can be produced, provided that these building boards are produced from a batch which comprises a component comprising calcium oxide, a component comprising silicon dioxide, expanded perlite, fibres and water, wherein the batch is shaped and the shaped batch is subsequently subjected to pressure and temperature in such a way that the component comprising calcium oxide and the component comprising silicon dioxide form xonotlite with the water.

[0078] Particularly surprising is the finding according to the invention that such a building board can be produced with the advantageous properties described herein, provided that the offset comprises expanded perlite.

[0079] The use of expanded perlite has, on the one hand, the above-mentioned significant advantages for the building board produced by the process, namely in particular the reduction of the density of the building board while at the same time ensuring high strength, good fire resistance and good mechanical workability of the building board.

[0080] In addition, the use of expanded perlite also has considerable advantages in the production of the building board: For example, it has surprisingly been found that the high absorbency of the expanded perlite, which it has due to its high open porosity, is very advantageous in the production of the building board. Due to the high absorbency of the expanded perlite, the water in the backfill required for the formation of the xonotlite can be largely absorbed by the expanded perlite and later released back into the backfill, especially during the application of pressure and temperature to the formed backfill and the resulting formation of xonotlite. However, due to the absorption of the water from the backfill in the expanded perlite, even backfill with a high water content is still easy to work and, in particular, can have a consistency similar to earth moisture rather than a slurry.However, due to the earth-moist consistency of the backfill, it is particularly easy to work with, and especially easy to shape. In particular, the backfill does not require additional drying before shaping.

[0081] In this respect, the process according to the invention can be carried out in particular as a semi-dry process.

[0082] In order to be able to fulfil these advantageous properties during the production of the building board by the method according to the invention, an expanded perlite with a high open porosity is provided, wherein the expanded perlite preferably has an open porosity with a proportion of more than 90 vol.%, based on the total volume of the expanded perlite.

[0083] Furthermore, it has been found according to the invention that the expanded perlite fulfils the above-mentioned advantageous functions during the production of the building board by the method according to the invention in particular when it is present in a specific grain size.

[0084] In this respect, according to a particularly preferred embodiment, the expanded perlite is largely or completely present with a grain size of at most 1.5 mm.

[0085] According to a preferred embodiment, at least 50% by mass, more preferably at least 90% by mass, and even more preferably 100% by mass of the expanded perlite in the batch of the inventive method has a grain size of less than 1.5 mm. Furthermore, at least 50% by mass, more preferably at least 90% by mass, and even more preferably 100% by mass of the expanded perlite has a grain size in the range of 0.01 to 1.5 mm. The stated mass fractions of expanded perlite in a specific grain size are each based on the total mass of the expanded perlite in the batch. The grain size of the expanded perlite can be determined by sieving in accordance with DIN EN 13055: 2016-11.

[0086] Preferably, the batch of the process according to the invention comprises the expanded perlite in a proportion in the range of 5 to 20 mass%, more preferably in a proportion in the range of 5 to 15 mass%.

[0087] The information given herein with regard to the mass fractions of a component of the backfill in mass % always refers to the total mass of the backfill, unless otherwise stated in the individual case.

[0088] According to the invention, it has been found that xonotlite can be formed from the calcium oxide-comprising component and the silicon dioxide-comprising component together with the water when the process according to the invention is carried out, in particular when the mass ratio of the chemical proportion of CaO to the chemical proportion of SiO 2 in the total mass of the calcium oxide-comprising component and the silicon dioxide-comprising component (i.e. the so-called C / S ratio) is above 1.00 and in particular above 1.00 and in particular at most 1.20. In this respect, the invention preferably provides that the mass ratio of the chemical proportion of CaO to the chemical proportion of SiO 2 in the total mass of the calcium oxide-comprising component and the silicon dioxide-comprising component in the batch of the process according to the invention is above 1.00, furthermore preferably at most 1.20 and particularly preferably in the range from 1.05 to 1.15.

[0089] The calcium oxide (CaO) component of the batch can comprise one or more calcium oxide-containing substances. If the calcium oxide component contains calcium oxide, this does not necessarily have to be in the form of calcium oxide. Rather, calcium oxide is the sole chemical component of the calcium oxide component, so the calcium can also be present in a form other than an oxide, for example, as hydroxide.

[0090] According to a preferred embodiment, the calcium oxide-comprising component of the batch comprises calcium hydroxide, i.e. Ca(OH) 2 . According to a particularly preferred embodiment, the calcium oxide-comprising component is in the form of calcium hydroxide.

[0091] Preferably, the batch comprises the calcium oxide-comprising component in a proportion in a range of 30 to 40 mass%, more preferably in a proportion in the range of 32 to 38 mass%.

[0092] The silicon dioxide (SiO 2 )-comprising component of the batch may comprise one or more silicon dioxide-comprising substances. If the silicon dioxide-comprising component comprises silicon dioxide, this does not have to be present in the form of silicon dioxide. Rather, silicon dioxide is the sole chemical constituent of the silicon dioxide-comprising component, so that the silicon may also be present in a form other than an oxide, for example, as silicic acid.

[0093] According to a preferred embodiment, the silicon dioxide-comprising component of the batch comprises quartz. According to a preferred embodiment, the silicon dioxide-comprising component is in the form of quartz. This quartz is particularly preferably in fine-grained form, in particular in the form of quartz flour. According to a preferred embodiment, at least 95% by mass of quartz or quartz flour, based on the total mass of the quartz, has a grain size of less than 200 µm, more preferably less than 160 µm.

[0094] Preferably, the batch comprises the silicon dioxide-comprising component in a proportion in the range of 17 to 27 mass%, more preferably in a proportion in the range of 20 to 25 mass%.

[0095] Preferably, the offset comprises fibers in a proportion in the range of 1 to 10 mass%, more preferably in a proportion in the range of 1.5 to 8 mass%.

[0096] According to a particularly preferred embodiment, the fibers are in the form of at least one of the following types of fibers: organic fibers or inorganic fibers.

[0097] Organic fibers may preferably be in the form of at least one of the following types of fibers: cellulose fibers or carbon fibers. If the organic fibers are in the form of cellulose fibers, they may particularly preferably be in the form of kraft cellulose fibers.

[0098] Cellulose fibers, in particular in the form of kraft cellulose fibers, are preferably present in the blend in a proportion in the range of 0.5 to 6% by mass, more preferably in a proportion in the range of 1 to 4% by mass.

[0099] Preferably, the cellulose fibers, in particular in the form of kraft cellulose fibers, have at least one of the following geometries: an average fiber diameter in the range of 10 to 30 µm or an average fiber length in the range of 0.5 to 3 mm.

[0100] Inorganic fibers can preferably be in the form of glass fibers, particularly preferably in the form of at least one of the following types of glass fibers: AES fibers, mineral fibers, basalt fibers, alumina fibers (Al 2 O 3 fibers), or silicate fibers (SiO 2 fibers). According to a particularly preferred embodiment, the glass fibers are in the form of AES fibers. The AES fibers can preferably have the properties of the AES fibers of the building board.

[0101] The batch preferably comprises glass fibers, in particular in the form of AES fibers, in a proportion in the range of 0.5 to 5 mass%, more preferably in a proportion in the range of 0.5 to 4 mass%.

[0102] The batch preferably comprises glass fibers, in particular with the above chemical composition, which have a classification temperature according to DIN EN 1094-1:2008-09 of at least 1,200°C.

[0103] The glass fibers preferably have an average fiber diameter in the range of 5 to 10 µm, more preferably in the range of 7 to 9 µm.

[0104] Preferably, the AES fibers have at least one of the following geometries: an average fiber diameter in the range of 5 to 15 µm (more preferably in the range of 7 to 9 µm) or an average fiber length in the range of 1 to 10 mm.

[0105] According to a particularly preferred embodiment, the fibers in the batch are in the form of AES fibers and kraft cellulose fibers.

[0106] Preferably, the offset comprises water in a proportion in a range of 15 to 35 mass%, more preferably in a proportion in a range of 20 to 30 mass%.

[0107] Based on the dry mass of the batch, i.e. the total mass of the batch without the water, the batch comprises the calcium oxide component, the silicon dioxide component, the expanded perlite and the fibers preferably in a proportion of at least 95% by mass, more preferably in a proportion of at least 97% by mass.

[0108] According to a preferred embodiment, the batch comprises the calcium oxide component, the silicon dioxide component, the expanded perlite, the fibers and the water in a proportion of at least 96% by mass, more preferably in a proportion of at least 97% by mass.

[0109] According to a preferred embodiment, the backfill comprises anhydrite in a proportion in the range of 0.5 to 3 mass%, more preferably in a proportion in the range of 1 to 2 mass%.

[0110] According to a preferred embodiment, the batch comprises a thickener. Such a thickener is a component that thickens the batch, making it easier to handle. According to a preferred embodiment, a thickener is in the form of at least one of the following substances: methylcellulose, xanthan, guar, or starch. The thickener is particularly preferably in the form of methylcellulose, particularly preferably in the form of a modified methylhydroxyethylcellulose, in particular in the form of a water-soluble, non-ionic, highly etherified methylhydroxyethylcellulose. The batch preferably comprises thickener in a proportion in the range of 0.2 to 0.6% by mass.

[0111] According to a preferred embodiment, the batch comprises a foaming agent. Such a foaming agent can form a foam or air bubbles in the batch. This can reduce the density of the batch and accordingly the density of the building board produced from it. At the same time, such a foaming agent can stabilize the batch. According to a preferred embodiment, the foaming agent is in the form of a surfactant. For example, a foaming agent can be present in the form of Sika®< foaming agent SB 2 (a trademark of Sika Deutschland GmbH). The batch preferably comprises foaming agent in a proportion in the range of 0.05 to 0.25% by mass, even more preferably in a proportion in the range of 0.05 to 0.1% by mass.

[0112] The batch of the process according to the invention comprises the calcium oxide component, the silicon dioxide component, the expanded perlite, the fibers, the anhydrite, the thickener and the foaming agent as well as the water, preferably in a proportion of at least 97% by mass, more preferably in a proportion of at least 99% and optionally also 100%, so that the batch can preferably comprise proportions of these components in the range from 97 to 100% by mass or even more preferably in the range from 99 to 100% by mass.

[0113] By shaping the backfill, the backfill is given a plate-like shape. The backfill is preferably formed by pressing. A particular advantage of the backfill of the method according to the invention is that it can be formed using a press according to the prior art for forming building boards, for example a press for forming cement building boards or other building boards for drywall construction. Since the water in the backfill, as previously explained, can be largely absorbed by the expanded perlite, the pressed boards prove to be mechanically very dimensionally stable. The backfill is preferably pressed using a pressing pressure in the range of 0.2 MPa to 0.32 MPa.

[0114] The advantage of the fact that the water in the backfill, as previously explained, can be largely absorbed by the expanded perlite is that practically no water is squeezed out of the backfill when it is pressed.

[0115] The compaction factor during pressing (i.e. the volume reduction of the offset during pressing) is preferably in the range of 2 to 3.

[0116] Before forming the backfill, it can be mixed to distribute the backfill components evenly throughout the backfill volume.

[0117] The formed batch is subjected to pressure and temperature in such a way that the calcium oxide component, the silicon dioxide component, and the water of the batch form xonotlite. Those skilled in the art are familiar with the necessary environmental conditions, in particular the necessary pressure and temperature, for forming xonotlite from these components of the batch through pressure and temperature.

[0118] Preferably, the batch is subjected to pressure and temperature in the autoclave. Preferably, a state-of-the-art autoclave, in particular an industrial autoclave, can be used. For example, an industrial autoclave such as that known for the production of sand-lime brick can be used.

[0119] When carrying out the process according to the invention, the batch is preferably pressurized in the range of 15 to 20 bar, more preferably in the range of 16 to 18 bar. Pressure in this sense is overpressure, i.e., pressure that exceeds the atmospheric pressure at the location of the measured overpressure.

[0120] Furthermore, the batch is preferably subjected to a temperature such that a saturated steam pressure is established, particularly at the aforementioned pressures. The temperatures required for this are known to those skilled in the art and can be determined, for example, using the vapor pressure curve of water. In this respect, the batch can be subjected to a temperature in the range of 200 to 220°C, for example.

[0121] The backfill is subjected to pressure and temperature for a period of time sufficient to form xonotlite from the components of the backfill. According to the invention, the backfill can be subjected to pressure and temperature for a period of time in the range of 8 to 20 hours, in particular for a period of time in the range of 12 to 16 hours.

[0122] During the application of pressure and temperature, xonotlite forms from the components of the backfill. Furthermore, during the application of pressure and temperature, depending on the composition of the backfill as well as the pressure, temperature, and duration of the application, other substances can form from the backfill, in particular at least one of the other substances calcium carbonate or other CSH phases.

[0123] Furthermore, the water content in the backfill can change during the exposure to pressure and temperature. This also results in differences in the composition of the backfill and the building board with regard to the respective mass fraction of certain components, such as expanded perlite, fibers, or anhydrite.

[0124] After applying pressure and temperature to the mixture or after autoclaving, a building board is obtained. This can then be dried, for example, preferably to a residual moisture content in the range of 8 to 12% by mass, based on the total mass of the building board.

[0125] Furthermore, the building board obtained by the method according to the invention can have the features of the building board disclosed herein.

[0126] The construction board can be used in drywall construction. For example, this can be done provided that the construction board is used to create partition walls, create ducts for electrical cables, create ventilation ducts, create smoke extraction ducts, or cover beams.

[0127] Further features of the building board and the method according to the invention emerge from the claims and the exemplary embodiment described below.

[0128] All features of the invention can be combined with each other in any way, individually or in combination.

[0129] An embodiment of the invention is described in more detail below. Example

[0130] According to one embodiment of the method according to the invention, a batch was first provided which comprised the components in the mass proportions according to the following Table 1, each based on the total mass of the batch: Table 1 component Mass fraction [mass%] Component containing calcium oxide 36,8 Component containing silicon dioxide 23,6 Expanded perlite 8,3 Cellulose fibers 1,3 AES fiber optics 0,6 anhydride 1,3 Thickener 0,2 Foaming agent 0,1 Water 27,8

[0131] The calcium oxide component was in the form of calcium hydroxide.

[0132] The silicon dioxide component was in the form of quartz flour. 95% of the quartz flour had a grain size below 50 µm, based on the total mass of the quartz flour. The quartz flour had a chemical composition of 99% SiO 2 , based on the total mass of the quartz flour.

[0133] The expanded pearlite had a grain size of less than 1.5 mm (100 mass%) and a grain size of less than 1.0 mm (98 mass%), based on the total mass of the expanded pearlite. Furthermore, the expanded pearlite had a grain size of between 0.03 and 1.0 mm (95 mass%), based on the total mass of the expanded pearlite.

[0134] The cellulose fibers were in the form of kraft cellulose fibers with an average fiber diameter of about 20 µm and an average fiber length of about 1.9 mm.

[0135] The AES glass fibers had a chemical composition, based on the total mass of the AES glass fibers, of 75 mass% SiO 2 and 22 mass% CaO + MgO. The average fiber diameter was approximately 8 µm.

[0136] The foaming agent was in the form of a surfactant (Sika ®< Foaming Agent SB 2) and the thickener was in the form of a modified methylhydroxyethylcellulose.

[0137] The total proportion of calcium hydroxide and quartz flour had a chemical composition in which the mass ratio of CaO to SiO 2 , based on the total mass of calcium hydroxide and quartz flour, was 1.103.

[0138] The mix was mixed in a mixer and then pressed in a commercially available hydraulic press with a punch for the production of fire protection boards at a pressure of 0.25 MPa into a square board with a side length of 1,250 mm and a thickness of 30 mm.

[0139] The pressed plate was then subjected to a pressure of 18 bar at saturated steam pressure and the resulting temperature (about 207°C) in an industrial autoclave for 12 hours.

[0140] Finally, the autoclaved plate was removed from the autoclave and dried in a drying cabinet to a residual moisture content of approximately 10 mass%.

[0141] The resulting building board was in the form of a building board with high fire resistance.

[0142] This building board comprised the following components in the mass proportions according to Table 2 below, each based on the total mass of the building board: Table 2 ingredient Mass fraction [mass%] Xonotlite 25,6 Expanded perlite 12,0 Cellulose fibers 1,8 AES fiber optics 0,9 anhydride 0,8 Calcium carbonate 1,2 Tobermorite 24,8 Calcium silicate gel phases 21,5 quartz 1,9 Scawtit 9,5

[0143] The mineralogical composition of the building board was determined by X-ray diffraction analysis using the Rietveld method.

[0144] During the microscopic examination of the building board, it was found that xonotlite had formed in the open pore volume of the expanded perlite, which largely closed the open pores of the expanded perlite.

[0145] The chemical composition of the building board was determined using X-ray fluorescence analysis according to DIN EN ISO 12676:2013-02. The building board contained the substances in the mass fractions shown in Table 3 below, each based on the total mass of the building board: Table 3 Chemical component Mass fraction [mass%] SiO2 45,44 Al2O3 1,79 Fe2O3 0,18 BaO 0,010 MnO 0,029 TiO2 0,043 V2O5 < 0,001 CaO 39,60 MgO 0,53 K2O 0,40 Na2O 0,59 SO3 0,09 Other < 0,05 Loss on ignition 11,26

[0146] To determine the fire resistance, the fire behavior of the building board was tested in accordance with DIN EN 1363-1:2012-10 using a support cladding test (box test) without a substructure, with the cladding components clamped. When exposed to temperature according to the standard temperature curve according to DIN EN 1363-1:2012-10, the onset of board sagging was only observed after 138 minutes and at a surface temperature of 1,011 K. The building board thus demonstrated excellent fire resistance.

Claims

1. A method for manufacturing a building panel with a high fire resistance, comprising the following steps:

1. providing of a batch, comprising: 1.1 a component comprising calcium oxide; 1.2 a component comprising silicon dioxide; 1.3 expanded perlite with a high open porosity; 1.4 fibers; and 1.5 water; 2. molding the batch; 3. exposing the molded batch to pressure and temperature, so that the component comprising calcium oxide, the component comprising silicon dioxide and water form xonotlite.

2. The method according to claim 1, in which the batch comprises the expanded perlite to at least 50 % by mass, relative to the total mass of the expanded perlite, in a grain size of at most 1.5 mm.

3. The method according to at least one of claims 1 or 2, in which the batch comprises the expanded perlite in a proportion ranging from 5 to 20 % by mass.